The
term Lithography literally means writing on stone in Greek.
Litho printing was discovered in 1798 by Alois Senefelder
and has grown into a popular printing process with artists
and commercially.
There are several steps involved in Senefelder’s
original Litho printing process. These have been modified,
adapted and innovated to become the offset lithographic printing
so popular today, but some arxtists feel that Senefelder’s
method allows for very high creative expression. The process
adds individual character to every creation that can never
be replicated.
Graining
The first step in the litho printing process
is graining. A limestone quarry North of Munich is the source
for the world’s most superior litho stones. A litho
stone must be grained after each use. A stainless steel disk
called a levigator is used to grain the litho stone with a
mixture of carborundum and water.
The stone is then ground with finer grit
leaving it smooth for the next drawing or painting. A new
litho stone is generally about 10 cm thick and only 1 mm needs
to be taken off for each new drawing. So a litho stone can
last for a few years if kept with care.
The Artwork
Once the stone has been grained and is ready
for the image, the artist must choose the image he wishes
to create. The first step is to draw a barebones outline of
the final image on tracing paper. Since the artwork on the
stone will have to be drawn in the reverse, tracing an outline
helps.
The finished line drawing is traced onto the
stone using a sheet smeared with iron oxide powder to act
as carbon paper. The iron oxide will leave a red outline of
the image that can act as a guideline for the artist. The
artist can then start drawing on the stone and filling in
all the details using oil based ink or a litho pencil.
In fact anything oily will leave an imprint
on the stone and can ruin the image so the artist must be
extremely careful when making the artwork. Sandpaper can be
used to sharpen the litho pencil if fine lines need to be
drawn.
Lithography uses just one surface area for
the image and non-image areas. Hence the two are separated
using a chemical process that involves an etch. An etch is
a solution of gum Arabic and nitric acid.
The first step of processing is to apply rosen
powder to the image area and wipe it off. Follow this with
a coat of talcum powder. The image area is then buffed vigorously.
Then the etch solution is applied using a brush over the entire
surface. The stone accepts this solution while the oiled image
area repels the solution. The etch is left for about five
minutes and then buffed off the stone.
Then comes the toughest part. An oil-based
solvent is poured over the stone and the entire image is washed
off. A thin layer of oil-based ink is then wiped over the
image area with a clean rag. The layer of water-soluble etch
gum is then removed.
A leather roller is then rolled on an ink
slab and rolled over the surface of the stone. The ink is
rolled several times over the stone and the stone is sponged
between each roll. The stone is then allowed to dry.
The entire process from rosen powder to rolling
ink is repeated several times to make the image as stable
as possible before printing.
The stone is inked with the ink color that
the image is to be printed in. Then a sheet of paper is laid
face down on the stone. A tympan or sheet of plexiglass is
placed on the paper. The press bed is then moved horizontally
to a point where the scraper bar is lowered onto the tympan.
As the scraper bar moves over the press bed, the image is
printed onto the paper. The paper is then removed.
The stone is immediately sponged wet and the
inking process repeated for another print. To print 50 copies
of the same drawing you would need at least 8-10 hours for
each color assuming you don’t have any problems during
the entire process.
Lithography
| Electron
beam lithography |
Printmaking
: Lithograpy | Large
area lithography |
Selecting
the right paper | Applications
Of Litho Printing | Lithographic
Printing Process |
